The present invention relates generally to a cosmetic stick for forming a powder stick or pencil, for directly applying powder to the skin.
One form of cosmetic stick is disclosed in German laid open application (DE-OS) No. 31 03 128, corresponding to U.S. Ser. No. 325,493; the cosmetic stick comprises a shaped body which is formed from powder base materials and pigments, possibly with the addition of binding agent, lubricant and/or adhesion-enhancing agent. In addition to the base materials, pigments and other additives which normally go to make up a powder pencil, the above-indicated cosmetic stick also includes a particulate material which is present in finely divided form and the particles of which are harder than all the other base materials. The aim and purpose of the additional particulate material is to prevent the surface of the powder stick or pencil becoming clogged with grease or moisture when the powder pencil is rubbed against the skin to apply powder thereto. In comparison with using powder from powder compacts, which is applied by means of an applicator, applying powder by directly rubbing the surface of the powder pencil against the skin has the advantage that it is easier to do and is more hygienic. However, the fact that the surface of the powder pencil becomes clogged, which may even occur in some cases after relatively short periods of use, is found to be an extremely troublesome aspect insofar as the surface of the powder stick becomes solid and glossy or glazed as a result of such clogging by such grease and moisture, so that it no longer deposits any powder on the skin of the person using the powder pencil, hence giving rise to the necessity for fresh powder to be exposed by for example making a fresh point on the powder pencil. The above-mentioned harder particulate material effectively prevents or at least reduces such clogging.
In the known cosmetic stick, the particulate material comprises quartz flour or substances derived from silicon dioxide, for example pumice powder and it is present in a proportion of 20 to 40% by weight, with a particle size of between 10 and 100.mu.. In that connection, a comparatively high proportion by weight of crystalline quartz can be considered to be a disadvantage from physiological points of view; in addition, those natural substances have a comparatively wide range of particle sizes so that expensive sifting operations have to be carried out after the grinding or crushing operation, in order to produce an at least relatively uniform particle size. Finally, additional cost is involved in avoiding contamination by other substances, possibly also including heavy metals which may be present, depending on the region in which the naturally occurring raw materials were mined.